Fuel tank filler pipe

Abstract

A fuel filler pipe for a fuel filler system of an automotive vehicle includes a generally helical directional control surface disposed within the fuel filler pipe and extending along the longitudinal axis thereof. The directional control surface guides fuel flowing through the filler pipe so as to impart a spiral flow to the fuel such that the fuel flows with reduced turbulence and subsequent vapor generation. In addition, the directional control surface restricts backward flow of fuel from the fuel tank through the fuel filler pipe.

We claim: 
     
       1. An apparatus comprising: a generally helical directional control surface adapted to extend within a fuel tank filler pipe and to a center thereof, with said helical directional control surface comprising an outer edge and an inner edge, with said outer edge adapted to lie adjacent an inner sidewall of the filler pipe and with said inner edge adapted to lie substantially along a central longitudinal axis of the filler pipe, with said helical directional control surface guiding fuel flowing through the filler pipe so as to impart a spiral flow to the fuel such that the fuel flows with reduced turbulence, thereby reducing vapor generation and with said helical directional control surface restricting backflow of fuel.   
     
     
       2. An apparatus according to claim 1 wherein said helical directional control surface extends within the filler pipe so as to complete at least one revolution. 
     
     
       3. An apparatus according to claim 1 wherein said helical directional control surface defines an inlet flow surface, with said inlet flow surface being generally concave. 
     
     
       4. An apparatus according to claim 1 wherein said helical directional control surface defines an inlet flow surface and a backflow surface, with said inlet flow surface being relatively smooth and with said backflow surface being relatively rough. 
     
     
       5. A fuel tank filler pipe for connection between an automotive fuel tank and a filler neck, with said pipe comprising: a cylindrical tube having first and second ends, inner and outer sidewalls and a longitudinal axis, with said first end adapted to be positioned toward the fuel tank and with said second end adapted to be positioned toward the filler neck; and,   a generally helical directional control surface extending within said tube and to a center thereof, with said helical directional control surface comprising an outer edge and an inner edge, with said outer edge lying adjacent an inner sidewall of said filler pipe and with said inner edge lying substantially along a central longitudinal axis of said filler pipe, with said helical directional control surface guiding fuel flowing through the filler pipe so as to impart a spiral flow to the fuel such that the fuel flows with reduced turbulence, thereby reducing vapor generation and with said helical directional control surface restricting backflow of fuel.   
     
     
       6. A fuel tank filler pipe according to claim 5 further comprising a chamfer formed between said inner sidewall and said second end of said tube, with said chamfer extending into said generally helical directional control surface. 
     
     
       7. A fuel tank filler pipe according to claim 5 wherein said helical directional control surface extends within said tube so as to complete at least one revolution. 
     
     
       8. A fuel tank filler pipe according to claim 5 wherein said helical directional control surface defines an inlet flow surface, with said inlet flow surface being generally concave. 
     
     
       9. A fuel tank filler pipe according to claim 5 wherein said inner edge of said helical directional control surface lies substantially along said longitudinal axis of said tube at least for a portion of the length of said helical directional control surface, with both said inner and outer edges lying adjacent said inner sidewall at said second end of said tube, thereby further restricting backflow of fuel. 
     
     
       10. A fuel tank filler pipe according to claim 5 wherein a longitudinally extending wall is formed between said inner edge of said helical directional control surface and said inner sidewall of said tube and extends toward said first end of said tube. 
     
     
       11. A fuel tank filler pipe according to claim 5 wherein said helical directional control surface defines an inlet flow surface and a backflow surface, with said inlet flow surface being relatively smooth and with said backflow surface being relatively rough. 
     
     
       12. A fuel tank filler pipe for connection between an automotive fuel tank and a filler neck, with said pipe comprising: a cylindrical tube having first and second ends, inner and outer sidewalls and a longitudinal axis, with said first end adapted to be positioned toward the fuel tank and with said second end adapted to be positioned toward the filler neck;   a generally helical directional control surface extending within said tube so as to complete at least one revolution, with said helical directional control surface comprising:   an outer edge attached to said inner sidewall of said tube;   an inner edge lying substantially along said longitudinal axis of said tube at least for a portion of the length of said helical directional control surface;   a relatively smooth inlet flow surface; and,   a relatively rough backflow surface; and, wherein said helical directional control surface guides fuel flowing through the filler pipe so as to impart a spiral flow to the fuel such that the fuel flows with reduced turbulence, thereby reducing vapor generation and with said helical directional control surface restricting backflow of fuel.   
     
     
       13. A fuel tank filler pipe according to claim 12 wherein both said inner and outer edges are attached to said inner sidewall at said second end of said tube, thereby restricting backflow of fuel. 
     
     
       14. A fuel tank filler pipe according to claim 12 further comprising a chamfer formed between said inner sidewall and said second end of said tube, with said chamfer extending into said generally helical directional control surface. 
     
     
       15. A fuel tank filler pipe according to claim 12 wherein said second end of said tube includes a rib extending around said outer sidewall of said tube for attachment to the filler neck. 
     
     
       16. A fuel tank filler pipe according to claim 12 further comprising a mounting flange disposed about said outer sidewall for mounting said filler pipe to the fuel tank. 
     
     
       17. A fuel tank filler pipe according to claim 12 wherein a longitudinally extending wall is formed between said inner edge of said helical directional control surface and said inner sidewall of said tube and extends toward said first end of said tube.